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Revert "Try using an ICE40_CARRY_LUT primitive to avoid ABC issues"

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This reverts commit a7632ab332.
This commit is contained in:
Eddie Hung 2019-04-17 11:10:20 -07:00
parent a7632ab332
commit c1ebe51a75
7 changed files with 36 additions and 103 deletions
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37
techlibs/ice40/arith_map.v
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@ -44,32 +44,25 @@ module _80_ice40_alu (A, B, CI, BI, X, Y, CO);
genvar i;
generate for (i = 0; i < Y_WIDTH; i = i + 1) begin:slice
ICE40_CARRY_LUT carry_lut (
SB_CARRY carry (
.I0(AA[i]),
.I1(BB[i]),
.CI(C[i]),
.CO(CO[i])
);
SB_LUT4 #(
// I0: 1010 1010 1010 1010
// I1: 1100 1100 1100 1100
// I2: 1111 0000 1111 0000
// I3: 1111 1111 0000 0000
.LUT_INIT(16'b 0110_1001_1001_0110)
) adder (
.I0(1'b0),
.I1(AA[i]),
.I2(BB[i]),
.CI(C[i]),
.CO(CO[i]),
.I3(C[i]),
.O(Y[i])
);
// SB_CARRY carry (
// .I0(AA[i]),
// .I1(BB[i]),
// .CI(C[i]),
// .CO(CO[i])
// );
// SB_LUT4 #(
// // I0: 1010 1010 1010 1010
// // I1: 1100 1100 1100 1100
// // I2: 1111 0000 1111 0000
// // I3: 1111 1111 0000 0000
// .LUT_INIT(16'b 0110_1001_1001_0110)
// ) adder (
// .I0(1'b0),
// .I1(AA[i]),
// .I2(BB[i]),
// .I3(C[i]),
// .O(Y[i])
// );
end endgenerate
assign X = AA ^ BB;